Exchange 2007

Only the demo version can be intsall on 32 bit.  Production must be 64bit.

Officially what MSFT has to answer your question:

"Q.      Why isn't Microsoft also delivering a 32-bit version of Exchange Server 2007?
A.      Exchange Server 2007 is designed to be a stable, reliable enterprise messaging platform that delivers the fundamentals of e-mail and calendaring while providing innovative new capabilities. These new capabilities make the messaging system more cost effective and scalable for your organization and at the same time more productive for users accessing the system. Simply put, given the new capabilities of Exchange Server 2007, Microsoft could not guarantee a high-quality 32-bit version."

Ref: http://www.microsoft.com/exchange/evaluation/topquestions.mspx?wt.svl=overview#EDE

You may want to increase your favorites link by reading these ones.

Exchange 2007 System Requirements
http://technet.microsoft.com/en-us/library/aa996719.aspx

Frequently Asked Questions
http://technet.microsoft.com/en-us/library/bb123811(EXCHG.80).aspx

Exchange Geek,

Thanks for you input. It's to bad that Exchange is not 32bit. A lot of users will go to other solutions.

Glad to have answered your query. Please contact us if you have any further query at EE Forum.

Take care.

Will do,

Thanks